1. Technical Field
The present invention relates to a color conversion device, a color conversion method and a color conversion program, and more specifically relates to a color conversion device, color conversion method and color conversion program for carrying out color conversion processing on color image signals, particularly in a case in which color reproducible regions of color image signals differ between a source device and a destination device.
2. Related Art
Devices which output color images include, for example, display devices such as CRTs, color LCDs and the like and printing devices such as printers and the like. Among these output devices, because respective output techniques and the like differ, the reproducible color ranges differ. In a CRT, because the output technique is a technique of causing a fluorescent material to illuminate, vivid colors can be displayed in regions of high brightness. In contrast, because the technique of a printer is displaying colors by superposing colorants, it is difficult to display colors with high brightness and high color saturation other than primary colors, but reproduction of colors with high saturations is possible for regions with lower brightnesses than with a CRT.
Thus, because the color reproducible region differs in accordance with an output device, in a case of, for example, printing an image prepared on a CRT at a printer, it may not be possible to reproduce colors displayed by the CRT at the printer. For example, colors with high brightness and high saturation can be outputted on a CRT but may not be reproducible with a printer. On the other hand, low-brightness, high-saturation colors can be reproduced by a printer but may not be capable of display at a CRT. Therefore, at least colors which cannot be reproduced are converted to colors which are considered closest thereto for output, such that it is possible to reproduce the whole of an image at an output device with the best possible quality. In such a case, color gamut mapping (gamut mapping) is necessary for converting supplied color image signals to colors within the color reproducible region of the output device.